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Skeletal System. Animal Science II Unit 5: Anatomy, Physiology and Absorption of Nutrients. Objectives. Name, locate and describe the functions of the parts of the skeletal systems of animals. Components of the Skelton. Bones Cartilage Teeth Joints Fig 5-1, 5-2
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Skeletal System Animal Science II Unit 5: Anatomy, Physiology and Absorption of Nutrients
Objectives • Name, locate and describe the functions of the parts of the skeletal systems of animals.
Components of the Skelton • Bones • Cartilage • Teeth • Joints • Fig 5-1, 5-2 • See p. 105 Major Differences Between Mammal and Avian Skeletal Systems • Quiz over beef skeleton on January 14
Cartilage • Tough connective tissue that is flexible and elastic • Forms the early skeletal structure of the embryo in vertebrate animals • As development occurs it is replaced by bone • Also found in • Joints • Trachea • Nose • Larynx • External ear • In the form of disc in the vertebral column
Bone Composition • Calcium compounds • Ossein • Small amounts of other minerals
Bone Growth & Development • Start out as cartilage • Transformation is carried out by specialized cells that break down the cartilage and replace it with bone cells called osteocytes • Flat bones of the skull develop from membranes • By birth most of the cartilage has been replaced by bone • Secondary bone development and growth occur as the animal matures
Bones Structure • Contain blood, lymph vessels and nerve fibers • Grow and repair themselves if damaged • Some have hollow centers that are filled with marrow • Marrow may be red, yellow, white or gelatinous • Type of marrow found is to some degree a function of age
Bone Marrow • Red Marrow • Forms blood cells • May only be found in animals with short life spans • Yellow, White, Gelatinous • Tend only to form in animals with life spans greater than 10 years
Bone Marrow Red Bone Marrow
Functions of the Skeletal System • Form • Protection • Support • Strength • With muscles attached the skeletal system acts as the levers to allow movement • Also store minerals and the bone marrow that produces blood cells
Types of Skeletal Systems Rigid Hydraulic Able to move by the application of force to a fluid confined in a small space and surrounded by muscle tissue Worms, Octopus and Starfish have this type of skeletal system • Able to move because muscles are attached • Two types • Endoskeleton-Vertebrate animals • Exoskeleton-insects, crustaceans
Kinds of Bones Cancellous Compact Composed of Haversian systems and usually found on the outside of bones and surrounding marrow Haversian system is composed of cylindrical or tubular structures of hard, inorganic material arranged in concentric layers. In the center there is the Haversian canal through which blood vessels and nerves pass Not found in small mammals or birds Fig 5-3 • Spongy • Generally found in the ends of long bones
Bone Shape • Long • Short • Flat • Irregular • Table 5-1
Parts of the Skeletal System • Axial • Skull • Vertebral column • Rib cage • Pectoral limb • Front legs • Pelvic limb • Hind legs
Joints • Synarthroses (fibrous) • Amphiarthroses (cartlaginous) • Diarthroses (synovial) • Classifications are based on the structure of the joint and the movement it is capable of
Synarthroses (fibrous) Joints • Joined by fibrous and in some cases cartilage tissue • Generally do not permit movement • Example: joints of the skull
Amphiarthroses (Cartiligionous) Joints • Consists of discs of fibrous cartilage • separate and cushion the vertebrae • Allow limited movement
Diarthroses (synovial) Joints • Allow free movement • Have a fluid filled cavity • Surrounded by ligaments that help hold the joint together • A synovial membrane is found inside the ligaments and the fluid from it lubricates the joint • Classifications • Ball and socket • Gliding • Pivot • Hinge
Summary • Mammal skeletal system is composed of bone, cartilage, teeth and joints • Cartilage forms the early skeletal structure of the embryo • Bones are made up calcium compounds, ossein and small amounts of other minerals • As bones grow the cartilage that makes up the early skeletal structure is replaced with bone cells called osteocytes • Bones contain blood, lymph vessels and nerve fibers • Some bones have hollow centers that contain marrow
Summary • Marrow may be red, yellow, white or gelatinous • The skeletal system provides form, protection, support and strength • Two types of skeletal structures-rigid and hydraulic • Two types of bones-cancellous and compact • 4 shapes of bones-long, short, flat and irregular • Skeleton is broken down into 3 parts-axial, pectoral limb, pelvic limb • Joints are classified based on their structure and type of movement